Bearing for gauge cutters of rotary rock bits



April 8, 1952 o. HAMMER 2,592,277

BEARING FoR GAUGE cuTTERs oF ROTARY Rocx BITS Filed May l5, 1948 f6 25 0 INVENTOR.

077-0 HAMMER Hrde/vins.

Patented Apr. 8, 1952 BEARING .FOR GAUGEJCU'ETERS' OF VROTARY ROCKBITS QttoHammer, Whittier, Calif., assigner toSecurity Engineering Co., Inc., Whittier, Calif., a corporation y oflCaiifornia Application May 15, .1948, SerialNof275245 3 Claims.

11 y .Thisinvention relates to vbearingsfor outer or .gaugecutterson rotary rock bits vof Athe so-called .cross-section type.

4.A primary object of the'invention is toprovide v.a `bearing for .the outer or gauge cutterof a rotary .rock bit which is, capable of carrying greater'loads .than the conventional roller and ball .bearings used Iforsuch cutters.

More-specically, Yan object of the invention is to provide a relatively simple and inexpensive ,bearingwhich may function as-a combined` radial bearing .and athrust bearing capable of 'carrying lnot `only. outer thrusts imposed on the cutter Lbut Aalso vinclude 'thrusts which arel frequently imposed .when'thegauge cutting corners yof thecutter teeth .become rounded or `dubbed oiT inthe rcourse -of wear.

',Recent technological radvances in well Ydrilling -practice require the imposition of "eX- tremely'heavy weights on the bit suchas, for

A such weights are'imposed thesdrillstemcannot be rotated ata Yhigh rate because of the danger of bearing failure when roller and ball-bearings are employed.

An object of the'present invention is to provide an'improved oearingof the-friction type wherein the vopposed surfaces of the bearing are formed ,of hard metals kand areso arranged as to provide not only 4strong -radial bearings but thrust'bearings 'to carry outward and inward thrusts that maybe-imposed on the cutter.

Another object of the invention is-to provide a bearing for rock bit cutters 'having the above vmentioned characteristics which can be easilyfand economically manufactured and readily .assembled with the cutter and installed.

With the-foregoing and other objects in view, which will be made manifest in the following detailed description and specifically pointed out theiappendedrclaims, reference is had to vthe tion; land .Fig. 3 is fa similar Aview to Fig. 2 and illustrating f-another 'alternative form of construction.

Referring -to the accompanying drawings wherein similar reference characters designate similar parts throughout, I@ indicates the body of a bit 'to which legs may be Asecured such-'as b v weld metal Il. One of such legs is indicated at I2 and-has a hollow.v journal Al.3.integral 'therewith. VThis journal,.in thepreferred'formofconfstruction, is externally stepped providing an outer portion Ifi .thatis ofsomewhat 'larger diameter than the inner portion i5. The gauge "cutter of the cross-section bit illustrated as 'shownat "I6 and the bridge III, conventionally employed in cross-section rock bits, has integral therewith a pin I8 which extends 'intothe central'aperturefin the journal and `'is anchored therein 'such "as-'by weld metal i9. An .inner 'cutter for kthe crosssection bit is indicated 'at 20.

In the construction illustrated in lFig. 1, 'the bearings uare provided 'by ywhat may be regarded as inner and outer AOpposed pairs Aof bushings or rings. The bushings or rings ofthe outer bearingare indicatedat 2| and 22. These rings'have their opposed surfaces grooved and iilledvwith.

hard metal'indicated at A23 and 24. In'a similar manner theinner bearing is composed of rings or 'bushings 25-and 23 which-are grooved and filled with hard metal indicated at 21'and2-8. AThehard Yof the journal. In -a'-similar-manner1the opposed iaces'of the hard metals and ofthe rings orfbushings lci" "the 'inner bearing are beveled or :inclined outwardly 'toward the axis of-` the rjournal. ,Consequently theV outer bearing Yfunctions as a'radial bearing and asa'thrust'bearing'fcr carryingfoutward thrustsimposedfon thecutter i6. In agsimilarr `manner-the inner bearingfunctions-not only as a radial bearing but as a thrustfbea-ring carrying inward thrusts that may be imposed-onvthe `cutter I6 when the gauge icutting corners :,ofthe teeth on the cutter becomerounded or are ydubbed off.

In the preferred form of 'construction the inner ring or bushing 2| ci the 'outer.- radial Ibearing can be pressed or shrunk onto the journalso as to-in eiectebecome integral therewith-andina similar manner the outer ring'or bushinglzgof the outer Vbearing'vniay be pressed into-the Vcutter it so as `to in-eiTect-become .integral therewith. Theinnerfring lor bushing 25 'canfalso be pressed into the Acutterlzuit the inner ring-or bushing .126 is inserted after the cutter has been slipped onto thereto within grooves.

are readily assembled prior to the assembly of the the journal and may be anchored in position such as by weld metal 29 prior to the assembly of the leg l2 with the bridge l1.

From the above described construction it will be appreciated that no space within the cutter is wasted to provide room for inner and outer thrust bearings which are independent of the radial bearings. The two bearings used function as radial bearings and thrust bearings combined wherein the outer bearing assumes outer thrust loads and the inner bearing assumes inner thrust loads applied to the cutter.

In the construction illustrated in Fig. 2, the arrangement of the bearings is substantially the same except that the hard metals 30 and 3| of the outer radial bearing are deposited in grooves that are formed directly in the cutter 33 and on the tapered surface of the journal 34. The hard metal 35 of the inner bearing can also be deposited in a groove directly on the interior of the cutter but the ha'rd metal 3G is deposited on a ring or bushing 31 similar to the ring or bushing 26 which can be anchored in position by means of weld metal 38. In this form of construction the bearings are likewise superior as radial bearings to the conventional roller bearing in that although they are of the friction type they are capable of carrying the heavy loads under high speeds required by the recent developments in Well drilling practice. The cuter bear ing by reason of its inclination to the axis of the journal functions not only as a radial bearing but as a thrust bearing for outer thrusts and the inner bearing similarly functions as a radial bearing and as a thrust bearing for inner thrusts.

The construction illustrated inV Fig. 3 is substantially the same as that illustrated in Fig. 2 except that the hard metal 39 of the outer bearing is deposited in a groove in a ring or bushing 40 in a manner similar to the manner in which the ring or bushing 2l is constructed. In this form of construction the hard metals applied to the interior of the cutter are welded directly The cutter and journal leg with the bridge and in so doing the ring or bushing 4| of the inner bearing is applied at the completion of the assembly of the cutter with the leg and welded to the journal such as by weld metal 42.

From the above described construction it will be Aappreciated that an improved bearing is -provided for the outer or gauge cutters of cross-section type bits which occupies a minimum amount of space within the cutter and by reason of its construction can assume the required radial loads and inner as Well as outer thrust loads.

Various changes may be made in the details oi' construction without departing from the spirit and scope of the invention as defined by the appended claims.

I claim:

1. A rotary rock bit having hollow journals for the gauge cutters thereof, a bridge between the journals having pins extending outwardly therein and welded therein, bushings telescoped onto the inner ends of the journals and welded thereon in positions in abutting relationship to the bridge, said bushings presenting outwardly tapering external surfaces circumferentially grooved and the grooves being filled with welded-on hard metal, the journals outwardly of the bushings presenting inwardly tapering external surfaces circumferentially grooved and the last-mentioned 4 grooves being filled with welded-on hard metal, cutters rotatable about the journals presenting internal surfaces complementary to said tapered surfaces and which are circumferentially grooved. the grooves in the cutters being filled with welded-on hard metal arranged in opposition to the hard metal on the bushings and on the journals. 2. A rotary rock bit having hollow journals for the gauge cutters thereof, a bridge between the journals having pins extending outwardly in the journals and welded therein, rings telescoped onto the outer ends of the journals presenting inwardly tapering external surfaces which are circumferentially grooved and the grooves filled with welded-on hard metal, bushings telescoped onto the inner ends of the journals and welded thereon in positions in abutting relationship to the bridge, said bushings presenting outwardly tapering external surfaces which are circum ferentially grooved and the grooves thereof being lled with welded-on hard metal, cutters rotat able upon the journals presenting internal surfaces complementary to the tapered surfaces on the rings and bushings and which are circumferentially grooved and which have the grooves thereof lled with welded-on hard metal arranged in opposition to the hard metal on the Arings and bushings.

3. A rotary rock bit having-hollow journals for the gauge cutters thereof, a bridge between the journals having pins extending outwardly in the journals and welded therein, rings telescoped onto the outer ends of the journals presenting,

inwardly tapering external surfaces which are circumferentially grooved and the grooves filled with welded-on hard metal, bushings telescoped onto the inner ends of the journals and welded thereon in positions in abutting relationship to the bridge, said bushings presenting outwardly tapering external surfaces which are circumferentially grooved and the grooves thereof being lled with welded-on hard metal, cutters rotatable about the journals having rings recessed therein and arranged in opposition to the mentioned rings and bushings, the rings on the cutters presenting outwardly and inwardly tapered surfaces complementary to the tapered surfaces on the rings and bushings respectively and which are circumfer-entially grooved and which have the grooves thereof lled with Welded-on hard metal arranged in opposition to the hard metal Aon the rings and bushings respectively on the journals.

OTTO HAMMER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Germany Apr. 6, 1929 

